The present invention relates to winding and, more particularly, to winding plastic tape on cores.
Plastic tape has become commonplace in a number of products including electrical products such as wire, cable, conduit, transformers and other electrical components, as well as in packaging. The use of plastic tape as ties in plastic garbage and storage bags has grown significantly. Manufacturers utilize plastic tape in the form of rolls in automated machinery to produce a wide range of these products.
Rolls of plastic tape are normally wound on cores to aid in winding and provide improved stability of the roll. They are sometimes wound as a single "pancake" package which comprises a single roll having a width equal to the width of the plastic tape or film. Such a roll has the disadvantage of becoming unstable at large roll outer diameters, especially if the tape is narrow. The single roll package also limits the length of plastic tape, requiring frequent stopping of the machinery for roll changes.
Another winding method for roll packages utilizes a helical winding method, similar to winding a reel of line or string. This method produces a roll package with a width greater than the tape width and provides additional capacity of the roll package as compared to the "pancake" roll package. This winding method suffers the disadvantage of instability, especially near the roll package ends. Use of spools with end discs improves the stability, but increases the complexity, cost and weight of the package.
U.S. Pat. No. 4,603,817 discloses a tape package comprising a winding method which incorporates a plurality of axially spaced wind positions. The wind positions are made up of a plurality of separate spiral windings of at least one turn. Helical windings connect spiral windings to adjacent positions. The spiral winding groups of the end positions have twice the windings of intermediate positions. Although this method has some advantages over other winding methods, roll density is reduced due to frequent helical winding transitions or steps, and end stability still limits wind diameter.